Acute coronary occlusion among cancelled STEMI alerts: a prospective study in a telemedicine-guided network.

Aims: ST-segment elevation myocardial infarction (STEMI) networks often face false-positive activations, leading to unnecessary catheterization laboratory use. To optimize resource allocation, STEMI alerts are sometimes cancelled after telematics evaluation; however, this strategy may result in missed cases of acute coronary occlusion (ACO) requiring urgent revascularization. Methods and results: This prospective, single-centre study included patients with initially activated but subsequently cancelled STEMI alerts via the ODISEA digital platform between January 2022 and December 2024. Based on coronary angiography, patients were classified as having ACO (TIMI 0-1 flow with thrombotic appearance) or no occlusion. Baseline characteristics, electrocardiogram (ECG) findings, angiographic data, and in-hospital mortality were compared. Of 2259 STEMI activations, 665 alerts (29.4%) were cancelled following a telematic assessment. Among these, 28 patients (4.2%) had ACO. Compared to the remaining cohort, they had higher rates of hypertension (78.6% vs. 60.3%; Conclusion: Among cancelled STEMI alerts, missed ACO cases were infrequent, often presenting with subtle or non-classical ECG findings. These patients showed a higher burden of cardiovascular risk and increased in-hospital mortality.